Short Answer
GSA MAS services modifications let you add or delete labor categories, add SINs, raise or lower rates, update labor category descriptions, and change administrative details. Catalog changes are made through a modification in eMod paired with a Services Plus File in the FAS Catalog Platform. Adding a SIN also requires relevant project experience.
Services contracts change as your business does. A new customer needs a role you don't have on contract. An agency plans to buy through a SIN you don't hold. Your rates need to keep up with the labor market. Each of these is a modification.
Here's a quick overview of the services modifications available, what each involves, and what to watch for.
How services modifications work
Every catalog change has two parts: a modification in eMod, which changes your contract and carries your supporting documents, and a catalog action in the FAS Catalog Platform (FCP), where you load a Services Plus File with the labor category data. Your contract must have an approved FCP baseline first. See The FCP Baseline Modification Explained.
The services modifications you can make
| Modification | What it does | What it typically needs |
|---|---|---|
| Add labor categories | Adds new roles to your contract | Cover letter, pricing support, labor category descriptions, Services Plus File, and a Service Contract Labor Standards matrix if applicable |
| Add SIN | Expands the services you can sell | Cover letter, relevant project experience (one project, or two for IT SINs), and pricing for the new SIN |
| Delete labor categories or SINs | Removes roles or SINs you no longer offer | Cover letter and updated file |
| Rate increase (EPA) | Raises rates under your contract's economic price adjustment method | Support under your method, such as an escalation rate, market index, or wage determination |
| Rate decrease | Lowers rates permanently or temporarily | Cover letter and updated file |
| Description change | Updates a labor category's duties or qualifications | Updated description and file |
| Revise Terms and Conditions | Updates contract terms, including setting your EPA method | Cover letter and updated terms |
| Administrative | Updates contacts, addresses and similar details | Cover letter and supporting documentation |
A few things worth knowing
Accept your mass mods first. GSA won't approve any modification while you have overdue mass modifications on your contract.
Labor category descriptions carry a lot of weight. Each needs duties, minimum experience and education, certifications, and how experience substitutes for education. Generic descriptions are one of the most common reasons labor categories get questioned as outside a SIN's scope.
Rates need support. Commercial rates are the strongest support. For roles that are new to your business, market data can help, but the contracting officer will compare your rates to the market either way.
Adding a SIN doesn't reset your contract. Only the additions are processed. Your existing labor categories stay as awarded, and existing categories can often be extended onto the new SIN.
Identical labor categories need identical prices. GSA won't award the same labor category at different rates under different SINs on the same contract.
Why services modifications get delayed
The most common causes we see:
- Labor category descriptions that don't clearly fit the SIN
- Project experience that doesn't match the new SIN's scope
- Rates without enough market or commercial support
- Services Plus File errors that fail FCP validation
- Choosing the wrong modification type in eMod
- Slow responses to the contracting officer
How long it takes
GSA doesn't set a timeline for modifications. Its guide cites averages of about 7 to 10 days for administrative mods and 10 to 30 days or more for others. Complete documentation and a clean file are the best way to avoid back-and-forth.
Let us handle it
Services modifications are where precise wording and clean data make the difference. We write the labor category descriptions, build the Services Plus File, prepare project experience for new SINs, and manage the modification through award, so your contract is ready when the opportunity arrives.
Frequently Asked Questions
Do I need project experience to add a SIN?
In most cases, yes. An Add SIN modification needs one relevant project with customer reference details and the statement of work, and IT SINs require two projects. The requirement is waived only in limited streamlined cases.
Will adding a SIN replace my existing labor categories?
No. An add modification covers only what you're adding. Your existing labor categories and SINs stay on the contract as awarded.
How do I raise my labor rates on GSA?
Through an economic price adjustment under the method on your contract, commonly a fixed escalation rate or a market index. Labor categories covered by the Service Contract Labor Standards are adjusted based on wage determinations.
How long does a services modification take?
GSA doesn't set a timeline. Its modification guide cites averages of about 7 to 10 days for administrative mods and about 10 to 30 days or more for others, depending on the contracting officer and how complete the submission is.
Written by Kurt Karslioglu, Director of Sales
Kurt leads business development at Pera Inc. and guides small businesses through GSA MAS offers, OASIS+ submissions, and federal construction and defense proposals.
Related Guides
GSA MAS Product Modifications: What You Can Change and How
Every type of GSA MAS product modification: adding and deleting products, price increases and decreases, descriptive changes and admin updates.
GSA MASThe FCP Baseline Modification Explained: Moving Your GSA Catalog to FCP
What the FAS Catalog Platform is, how the FCP baseline works, what you can and can't change, and why baseline files fail validation.
GSA MASYou've Been Awarded a GSA Schedule. What Happens Next?
After a GSA MAS award: loading your catalog in FCP, the Terms and Conditions file, sales reporting, the Industrial Funding Fee, mass mods and minimum sales.